History, World War II

King Ananda, Western colony, British Burma, King Bhumibol Adulyadej, Japanese troops

In 1940 Thailand fought a brief war with French Indochina, which had become cut off from France as a result of World War II. With Japanese mediation, the Thai government regained the territories in Laos and Cambodia that had been ceded to France in 1904 and 1907. On December 8, 1941, Japanese troops landed on Thailand’s southern coast. This was around the same time that the Japanese launched attacks on Pearl Harbor, Midway, Guam, Manila, Hong Kong, and other sites. After tense meetings with the Japanese and his cabinet, Phibun agreed to allow the Japanese to move their troops through Thailand to invade and occupy the British-controlled Malay Peninsula, Singapore, and Burma. In January 1942 Thailand declared war against Britain and the United States. In 1943 Japan rewarded the Phibun government for its cooperation with the Japanese by awarding Thailand part of the territory that had been incorporated into British Burma in 1885 and the four Malay states that Siam had been forced to cede in 1909.

Meanwhile, considerable anti-Japanese sentiment was developing in Thailand. With aid from the United States government, Pridi and M. R. Seni Pramoj, the wartime Thai ambassador to the United States, organized the underground Free Thai Movement to agitate against Japanese influence. In July 1944, as the war began to turn against Japan, Phibun was forced from office, and Khuang Aphaiwong, a civilian, took over as prime minister. Pridi continued to be a major power behind the scenes. When the war suddenly ended in August 1945, M. R. Seni Pramoj returned to become prime minister. He faced not only chaos and the disruption caused by nearly four years of Japanese presence but also extensive demands by European nations that threatened to turn Thailand into a Western colony. With strong American support, Thailand successfully resisted these pressures. However, the Thai government did restore to Britain and France the territories in Indochina, Burma, and the Malay Peninsula that it had gained during the war. After doing so, Thailand was admitted to the United Nations (UN) in December 1946.

In June 1946 King Ananda died under mysterious circumstances, an event for which many irrationally blamed Pridi and others seen as opposing the monarchy. Ananda’s younger brother succeeded to the throne as King Bhumibol Adulyadej (Rama IX), but a regency council ruled until 1951 while Bhumibol completed his studies abroad.